Folding wing projectile



NOV. 29, 1960 ROSENTHAL 2,961,928

FOLDING WING PROJECTILE Filed Nov. 3, 1958 2.5heets-Sheet 2 "A If INVENTOR. Henry Rosennhal FOLDING WING PROJECTILE Henry Rosenthal, Washington, D.C. (132 Carpenter Ave., (Irestwood, Tuckahoe R0. 7, N. Y.)

FiledNov. 3, 1958, Ser. No. 771,684

2 Claims. (Cl. 891.7)

(Granted under Title 35, US. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty thereon.

This invention relates to a folding wing projectile and more particularly to a projectile that is equipped with folding wings to provide sufiicient air lift to supply the projectile with substantially a fiat trajectory.

An object of the invention is'to provide a projectile having a low or flat trajectory.

Another object of the invention is the provision of a low velocity projectile that may be fired with accuracy at a target, and whose hit probability will not be substantially reduced by usual errors in range estimation.

Another object of the invention is to provide a projectile whose hit probability will not be affected substantially by round to round variations in muzzle velocity.

Another object of the invention is to provide a projectile whose hit probability will not be affected substantially by muzzle velocity variations due to temperature of the propellent.

A still further object of the invention is to provide a low velocity projectile with airfoil wing members.

Other objects and advantages of the invention will be apparent during the course of the following description.

In the accompanying drawings, forming a part of this specification, and in which like numerals are employed to designate like parts throughout the same,

Fig. 1 illustrates a top plan view of an embodiment of the invention, its wing members being folded and positioned within a barrel of a recoilless gun, the gun barrel being shown in fragmental longitudinal section,

Fig. 2 is a fragmentary elevation of the projectile shown in Fig. 1 and rotated at an angle of 90,

Fig. 3 is a fragmentary plan view of the forward portion of the projectile after firing, the wing members being fully extended,

Fig. 4 is a cross section taken along lines 4--4 of Fig. 1 and looking in the direction of the arrows,

Fig. 5 is a cross section taken along lines 5-5 of Fig. 2 and looking in the direction of the arrows,

Fig. 6 is a greatly enlarged detail sectional view taken along lines 6--6 of Fig. 3 and looking in the direction of the arrows,

Fig. 7 is a cross section taken along lines 7-7 of Fig. 3 and in the direction of the arrows, illustrating the air foil contour of the wings, and

Fig. 8 is a fragmentary plan view of the forward portion of a projectile illustrating the wings in fully extended position wherein they lie in the center of gravity of the projectile.

Referring now to the drawings in which 1 designates generally the projectile of the invention, and, as is illustrated in Fig. l, is in a firing position in a recoilless gun barrel shown somewhat schematically and in longitudinal section as by 2. Barrel 2 is provided with a longitudinal fin groove 3 and a pair of diametrically disposed longitudinal wing grooves 4. (See Fig. 4.)

or lifting position as seen in Fig. 3.

2,91923 Patented Nov. 29, 1950 Groove 3 lies in a plane intersecting the plane of grooves 4 at and is preferably positioned at the upper most portion of the barrel when the weapon is in the firing position. This groove will thus serve to position the round in the weapon in a manner that stabilizing fin 9 is vertical and at the top of the projectile as it leaves the weapon. The groove thus acts to index the projectile and at the same time allows the use of a larger stabilizing fin than would be possible without a groove.

Projectile 1 is illustrated as a HEAT round of ammunition such as may be used in a recoilless weapon and consists of a body 5, a forwardly extending spike 6, a tail 7 and a fixed fin assembly 8 and in addition projectile 1 is provided with a stabilizing fin 9 fixed on the body and tail portions.

A pair of diametrically disposed wings 10 are pivotally mounted on the body 5 of projectile 1 for movement from a folded position as shown in Fig. 1 to an extended One manner by which wings 10 are pivotally mounted to the body 5 is illustrated in the drawings for example: Each wing is connected to a reduced portion 12 on the forward portion of body 5 by angular straps 11 which are pivoted at one of their ends to the reduced portion 12 as at 13 somewhat beyond the peripheral surface of body Sin order to ride in grooves 3 and 4 respectively when projectile 1 is in barrel 2 as seen in Fig. 4.

.A pair of diametrically disposed notches 16 are provided in the face of second shoulder 15 and lie in the same plane as wings '10, whereby when wings 10 are in fully extended position, the trailing edges thereof will be received in the notches for reinforcement during flight.

Suitable means to lock wings 10 in the aforesaid extended position while in flight are provided, and one method by way of example is illustrated in Fig. 6. A pair of rounded detents 17 are slidably mounted in a transverse bore 18 in wings adjacent a rearrnost corner. The detents are biased in opposed directions by a spring 19. When wings 10 are in their fully extended position, the detents will be received in rounded recesses 20 in the walls of notches 16.

As is illustrated in cross section, each wing 10 is of air foil contour to provide a lift to the projectile 1 while in flight. When opened the wings should be positioned at an angle of attack to provide a lift when the projectile moves through the air at substantially the velocity at which it is intended to be fired. It is further desirable for the lateral stability in flight that when the folding Wings are extended they form a dihedral angle. The fixed wings 8, promote longitudinal stability in flight. The folding fins should be so positioned fore and aft, when in the open position, that they cooperate with the fixed fin 8 in providing suitable longitudinal flight stability.

In practice, projectile 1 is loaded in barrel 2 with wings 10 in their folded position, wherein the forward edges of wings 10 lie against spike 6 and their inner ends are adjacent first shoulder 14. In loaded position in the barrel 2, the trailing edges of wings 10 ride in wing grooves 4 and the outer edge of fin 9 rides in the fin groove 3 thereby aiding in stabilizing the projectile when fired to prevent spinning movement relative to the barrel 2. Upon emerging from the muzzle end of the barrel (not shown) wings 10 automatically pivot outwardly to a fully extended position as seen in Fig. 3. As reduced is offered during the pivotal motion and the trailing edges of the wings are received in notches 16 in the second shoulder and the inner ends of wings 10 are adjacent the peripheral surface of reduced portion 12. Upon reaching the fully extended position, the wings are locked by the spring biased detents 17 which snap into rounded recesses in the walls of grooves 16 to be locked in the fully extended position throughout projectile flight.

Wings 10 may be arranged to extend to their flight position whereby they lie near the longitudinal center of gravity of the projectile as illustrated in Fig. 8. This is accomplished by varying the length of straps 11 and the location of pivots 13 and 13 whereby the wings will extend to a point rearwardly of the reduced portion 12, the center of gravity being indicated by C. Wings 10 may be secured in their extended position by suitable detents, etc., as indicated by 17 Since wings 10 are designed in air foil contour, an air lift to the projectile is effected and thus insuring a flight that will be as flat as is possible for the particular projectile. This, of course, occurs automatically and results in the projectile, particularly a low velocity projectile, that can be fired into a maximum of accuracy heretofore not possible.

It is to be understood that the form of the invention shown and described, is to be taken as a preferred example of the same, and that various changes in the shape, size and arrangement of parts may be resorted to, with- .out departing from the spirit of the invention, or the scope of the subjoined claims.

What is claimed is:

1. A projectile including a body having an integral reduced portion at its forward end and an integral spike portion extending forwardly from said reduced portion and in coaxial relation with said body, there being a rounded shoulder formed by said reduced portion, said shoulder having a pair of diametrically disposed slots in its face thereof, each said slot having a pair of opposed recesses in its side walls thereof, a pair of wing members mounted on said reduced portion on said body for pivotal movement in a substantially horizontal plane between a retracted position whereby the forward edges of said wing members are disposed in parallel relation adjacent said spike portion to an extended lifting position whereby the inner edges of said wing members are in parallel relation adjacent said reduced portion on said body and a portion of the trailing edges of said wing members are received in said slots in said shoulder in said body, and means locking said wing members in their extended position comprising a pair of diametrically opposed spring biased detents housed in said wing members adapted to be received in said recesses in said slots.

2. In an ordnance apparatus, the combination including a gun barrel, said gun barrel having at least one longitudinally extending stabilizing groove and a pair of diametrically opposed, longitudinally extending Wing grooves, said stabilizing groove and said wing grooves extending in parallel relation with the axis of said barrel, a projectile for firing in said gun barrel, said projectile including a body, a stabilizing fin secured to said body for engagement in said stabilizing groove when said projectile is positioned for firing in said gun barrel and wing means mounted on said body, said wing means comprising a pair of wing members mounted for movement in a substantially horizontal plane from a retracted to an extended lifting position, said wing members having an airfoil cross section so as to effect an air lift and provide a fiat trajectory for said projectile during its flight, said pair of wing members engaging said wing grooves when said projectile is in position in said gun barrel, the wing members being movable from said retracted position upon firing of said projectile outwardly of said gun barrel to said lifting position.

References Cited in the file of this patent UNITED STATES PATENTS 2,427,217 Lebherz et a1 Sept. 9, 1947 2,430,896 Uhl et al Nov. 18, 1947 2,701,984 Terce Feb. 15, 1955 2,900,873 Wust Aug. 25, 1959 FOREIGN PATENTS 262,445 Germany July 14, 1913 89,970 Sweden Aug. 10, 1937 3) Ann- 

